Response of Agronomic Characteristics and Yield of Garlic Plant (Allium sativum L.) to Different Levels of Planting Density and Nutrition

Introduction[1] Garlic (Allium sativum L.), a member of the Liliaceae family, is the second most important crop after onion (Allium cepa L.) among vegetables. It is widely used as a food spice and medicinal herb in many parts of the world, making it one of the key crops cultivated during the cool season. Garlic economic yield is affected by various agronomic factors such as optimum planting distance (plant density) and proper supply of the required nutrition (proper nutrition) of this plant. The selection of suitable planting density can increase the productivity of crops. On the other hand, meeting the nutritional needs of crops is also a great necessity in order to increase the production of crops. Humic acid, as a natural and environmentally friendly organic acid, has a positive effect on the absorption of nutrients by crops, and it is very important for the transfer and availability of micronutrient elements in the plant. The most important factor limiting crop yield in many parts of the world macro and micronutrient deficiency in soil is more. Suitable nutrition due to the balanced application of fertilizers, with regard to the physiological needs of crops, can reasonably provide access to the expected yield. Nutrition is another factor affecting the growth and performance of garlic plants. Research has shown that the growth and yield of this plant are largely influenced by the management of the supply of various nutrients. Materials and Methods This experiment was conducted as a factorial layout based on a randomized complete block design with three replications during the growing season of 2016- 2017 at the experimental field of Beiranshahr city of Khorramabad in Lorestan Province, Iran. Before conducting the experiment to determine the physical and chemical properties of soil samples were collected from 0-30 cm depth of soil. The treatments were comprised of two factors were studied: Planting density at three levels: D1, D2, D3; 32, 42, and 52 Density (Plant. m-2), respectively, and Nutrition On four levels: N1, N2, N3, and N4 (control, Humic acid, totalize fertilizer 20-20-20, Humic acid+Totalize fertilizer 20-20-20), respectively. For treated with humic acid, Garlic cloves before planting in a proportion of 50 ml per kilogram, Clove was treated. Totalize fertilizer 20-20-20 was used at the rate of 80 kg/ha in the farm. Traits such as plant height, stem diameter, leaf number, Garlic diameter, cloves number in garlic, Garlic weight, and economic yield were measured. In this study, Hamedan White Garlic was used for cultivation. Results and Discussion The results indicated that the main effects of nutrition, plant height, and the number of cloves in garlic were significant, as well as the interaction between planting density and nutrition (treatment 42: density in plants per square meter with Totalize fertilizer 20-20-20). Significant increases were observed in stem diameter, number of leaves, garlic diameter, garlic weight, and economic yield. The analysis of variance (Table 4) revealed that nutrition had a significant effect on plant height (p ≤ 0.01). The main effect of planting density was significant (p ≤ 0.05), while both nutrition (p ≤ 0.001) and the interaction of planting density and nutrition (p ≤ 0.01) significantly affected stem diameter and the number of leaves. Additionally, nutrition and the interaction of planting density and nutrition had significant effects on garlic diameter (p ≤ 0.001). According to the analysis of variance (Table 4), nutrition had a significant effect (p ≤ 0.01) on the number of cloves. The results also demonstrated that the main effects of density and nutrition, as well as their interaction, positively and statistically significantly influenced garlic weight and economic yield at the p ≤ 0.001 level. Conclusions The results of this experiment showed that the garlic plant exhibited varying responses to different planting densities and levels of nutrition. Increasing planting density reduced plant height, stem diameter, leaf number, garlic diameter, Cloves number in garlic, and garlic weight. Increase the plant density of garlic from 32 to 42 to 52 plants. -2 significantly increased the economic yield, respectively. Because of the increase in garlic planted per hectare. The results showed that the effect of different levels of Planting Density and Nutrition was significant on garlic grain yield. The highest mean of garlic grain yield as a provisioning service was obtained from 42 Plants per m-2 in nutrition with totalize fertilizer 20-20-20 (25756 kg. ha-1), and the lowest garlic grain yield was obtained in control treatment with non-fertilizer application and 32 plants per m-2 (14314 kg.ha-1). Therefore, with the optimal use of this fertilizer (Humic acid and total fertilizer), the effects of growth and yield on plants are somewhat enhanced, and it is recommended for use in a similar climate.